html, body {
    height: 100%;
}

body {
    background: url("../img/login_bg.jpg") center center no-repeat;
    background-size: cover;
    overflow: hidden;
}

.input-group {
    padding: 30px 0;
}

.container {
    display: none;
}

.tips {
    color: #000;
    text-align: center;
    opacity: .7;
    margin-bottom: 10px
}

.input-group {
    position: relative;
}

span.alert {
    display: none;
    position: absolute;
    width: 100%;
    left: 0px;
    bottom: -40px;
    padding: 8px 20px;
}